Effects of joints on the cutting behavior of disc cutter running on the jointed rock mass

The rock breaking mechanism is significantly affected by the joints in the rock mass. With the purpose to study the influence of joint characteristic parameters on cutting force and penetration, experimental explorations that contain miniature cutter head with double cutters are conducted in this paper on the basis of Rolling Indentation Abrasion Test (RIAT). In the present research, prefabricated joints of different forms are made in the rock samples. The experimental conclusions indicate that the optimal angle between horizontal and joint plane is equal to 30 degrees for rock breaking process. In detail, the minimum thrust and the maximum penetration, which are related to the rock chipping angle for different joint orientations, are obtained at the optimal angle. Meanwhile, the improved theoretical formulas which are suitable for both intact and jointed rock are proposed. Besides, the change of thrust with penetration can be divided into four stages, which are the loading, starting, boring and stripping stages. Through simulating the rock breaking process by the rock rolling boring experimental method, this study measures the thrust, torque, penetration on the disc cutter, and reveals the influences of joint orientation and spacing on cutting forces and penetration. Furthermore, the penetration variation is summarized and the results are in good agreement with the field observation and numerical simulation results.